Physics of Semiconductor Devices

Band structure

In a certain semiconductor, the valence band can be approximated by the function E = E₀ - αk² and the conduction band can be described by the function E = E₁ + βk². Here E is the electron energy and k is the wavenumber.

(a) What is the band gap of this semiconductor?

(b) Is this a direct or indirect bandgap semiconductor?

(c) What is the effective mass of the electrons and holes?

Express your answers in terms of E₀, E₁, α and β.